Phosphorylated chitosan (P-chitosan) was synthesized by means of graft copolymerization technique. The conjugate membranes were prepared from oxidised starch and P-chitosan using reductive alkylation crosslinking. The synthesized membranes were characterised by FT-IR. In order to characterize degradation behaviour of this conjugated system, the membranes were incubated in enzyme solutions of alpha-amylase and lysozyme as well as a physiological saline solution (PBS) used as control solution. In PBS, low starch containing membranes (0.16-0.38 weight ((starch))/weight ((P-chitosan)), (w(s)/w(c))) and control membranes have not showed significant change in their weight during two months of incubation. High starch containing membranes (0.73-1.04 w(s)/w(c)) indicated less than 20% weight loss after this period. After a-amylase incubation, a distinct degradation behaviour was observed from starch-P-chitosan membranes. The degradation of the conjugate membranes was found to be fast with increasing starch content. Weight losses between 20 to 55% were detected for the lowest (0.16 w(s)/w(c)) starch and highest (1.04 w(s)/w(c)) starch containing membranes, respectively. In the lysozyme degradation study, the conjugate membranes were not degraded by enzymatic activity and the weights of membranes were seen to be increased about 20% because of swelling. The control membranes showed gradual weight loss in enzyme solutions. These results indicated the lysozyme degradation of starch-free P-chitosan membranes and inhibition of degradation P-chitosan by highly conjugated starch molecules.